Figure 4.

The nuclease domain of Dna2, but not helicase or checkpoint domains, confers viability of dna2∆ strains. (A) Domain structure of yeast Dna2. Mutations affecting checkpoint, nuclease, and helicase domains are indicated. (B) Spot test assay performed as in Figure 2B. Strains from passage 6 of original colony 3a (rad9∆ dna2∆, DLY10967), and 13d (ddc1∆ dna2∆, DLY10973) were used for plasmid transformation. rad9∆ dna2∆ and ddc1∆ dna2∆ strains carrying DNA2, empty vector or helicase-dead, nuclease-dead or checkpoint-dead alleles of DNA2 were inoculated into 2 ml –URA or –TRP media for plasmid selection and cultured for 48 hr, at 23°. Original images are in Figure S8 in File S1. Strain details are in Table S1 in File S1. Plasmid details are in Table S2 in File S1. N.C., no complementation.